JPH0238239B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sewing machine and, more particularly, to a device included in a sewing machine for employing a needle lateral movement mechanism along an edge.

There are many applications where it is desirable to sew a series of stitches at a substantially constant distance from the edge of the fabric. To meet this need, a number of devices have been developed to sense the edge position and guide the fabric accordingly. Such devices are typically extremely complex and expensive to supply and have therefore found only limited acceptance, i.e., they have generally been confined to the field of industrial sewing machine equipment. However, many home sewing machine users may be interested in having such features in their sewing machines. It would therefore be desirable to have a simpler and less expensive device for making seams at a predetermined distance from the edge of the fabric. It would also be desirable to provide such a device for incorporation into a domestic sewing machine.

It is therefore an object of the invention to provide a device for guiding seams that is simple and inexpensive.

Another object of the invention is to provide such a device that can be incorporated into domestic sewing machines.

The foregoing and incidental objects are to provide, in accordance with the principles of the present invention, a method for sewing a series of stitches at a substantially constant predetermined distance from the edge of a fabric using the ability to laterally move the needle of a domestic sewing machine. This is accomplished by providing a device to guide the seams. Typically, a device is provided for sensing the position of the edge of the fabric near the needle and for providing a signal representative of the distance between the edge and the needle. Associated equipment is also provided for controlling a needle lateral movement mechanism within the sewing machine in response to this signal to position the needle laterally at a predetermined distance from the edge.

In accordance with the nature of the invention, the device also includes a device for providing user-controlled settings that are adjustable over a predetermined distance.

Referring to the drawings, like components in each drawing have been given like reference numerals, and FIG. Shown and illustrated. Sewing machine 10 has bed 1
2, includes a post 14 extending upright from the bed 12, and a bracket arm 16 projecting above the bed 12. The drive mechanism of the sewing machine includes an arm shaft 18 timeably interconnected by a known drive mechanism including a drive motor (not shown).
and bedshaft (not shown).
The needle 20 is connected to the gate 2 in the bracket arm 16.
4, the needle bar 22 is attached to the needle bar 22 so as to move laterally, and the needle bar 22 is moved to make a reciprocating movement up and down. Any coupling component may be used between arm shaft 18 and needle bar 22 to transmit reciprocating movement of the needle.

To impart lateral movement to the needle 20, the drive link 26 is pivoted at 28 relative to the gate 24, illustratively as described in U.S. Pat. No. 4,016,441, issued April 5, 1977. mechanically connected to a reversible linear actuator 30 of the type described. This linear actuator 30 may therefore be controlled to determine the lateral position of the sewing needle 20, as illustrated by way of example in U.S. Pat. No. 3,984,745, issued October 5, 1976. , the disclosure of which is hereby incorporated by reference.

To move the fabric 32, a feed dog 34 extends out of the bed 12 through a slot 36 in the needle plate 38.

FIG. 1 shows a timing pulse oscillator 40, which may be of the type illustrated and described in U.S. Pat. No. 3,939,372, issued February 17, 1976.
is also illustrated. The pulse oscillator 40 provides a series of timing pulses, one for each revolution of the armshaft 18.

In accordance with the principles of the present invention, the sewing machine 10 is equipped with a device for sewing a series of stitches at a substantially constant distance from the edge 44 of the fabric 32. Rim 44
Although illustratively shown as straight, the present invention is intended to be effective within the limits of the range of lateral travel of needle 20 regardless of the contour of edge 44.

Once upon a time, when a user of a known domestic sewing machine wished to sew a series of stitches at approximately a fixed distance from the edge of a piece of fabric, the edge of the fabric was held at that predetermined distance from the needle. I had to guide them very carefully. To assist the user in this regard, various methods of edge guidance have been developed, including, for example, the use of lines drawn with a marker on the needle plate of the sewing machine. however,
None of these designs actually control the spacing between the edge of the fabric and the series of stitches.

Accordingly, the invention in question provides a method of adjusting the lateral position of the needle at a substantially constant predetermined distance from the edge of the fabric by adjusting the lateral position of the needle to compensate for that laterally from the desired line of travel of the edge of the fabric. It is designed to help you sew a single stitch. To achieve this result, the bracket arm 16 is provided with a switch 46 which is used by the user when it is desired to operate the sewing machine 10 in the edge guiding mode. An edge sensor 50 is provided to sense the position of edge 44. This is illustratively of the type described in US Pat. No. 3,609,373, issued September 28, 1971, the disclosure of which is hereby incorporated by reference. The edge sensor 50 has a first photo sensor 52 spaced one or two stitches in advance of the needle 20;
a second photo sensor 54, both of which are mounted on a bed plate 56.
located within. The sensor 52 has an elongated rod-like structure whose position is longitudinally adjustable to set the desired position of the edge 44 in the center of the sensor 52. When the sensor 52 is so adjusted, the lateral distance between the center of the sensor 52 and the center needle position is reduced by a series of stitches 42 and edges 44.
equal to the desired spacing between. Sensor 54 is a reference sensor placed in an area that would be substantially covered by fabric 32 at any time during normal sewing operations. This sensor 54 is used to monitor the transparency of the fabric and provides information that is used to modify the signal from sensor 52 so that sensor 54 contains information only related to errors in the position of edge 44. . Referenced U.S. Patent No.
3609373, for details regarding Figure 2b,
As fully disclosed and explained, a voltage is applied to lead 58 and this voltage is applied to sensor 5.
2 and represents the difference between the actual and desired position of the edge 44. The value of the circuit components within the edge sensor 50 is edge 4.
4 is present at the top of the center of the sensor 52,
The voltage on lead 58 is selected to be zero, and a negative voltage, e.g., a signal of the first polarity, indicates that more of the sensor 52 is covered by the fabric 32, i.e., the edge 44 is Corresponding to the shift to the right in Figure 1, e.g. along a first direction, a positive voltage e.g.
2 is covered by the fabric 32, i.e. the edge 44 is on the left in FIG. 1, e.g.
It is made to correspond to the deviation along the second direction.

As explained and disclosed in the above-mentioned U.S. Pat.
It is stored in ROM60. The feed information signal is transmitted from pattern ROM 60 to feed operator device 62 at the appropriate time. Similarly, the byte information signal is
At the appropriate time, it is transmitted from gate 66 through latch 68 to bite actuator device 64, which includes actuator 30. However, the switch 46 that guides the edge
is closed, the transmission gate for byte information from pattern ROM 60 is disabled and the transmission gate from analog-to-digital converter circuit 70 is enabled instead. This analog
The input to the digital transducer circuit 70 is position information on the lead 58 from the edge sensor 50, which is used to determine the position of the needle in order to maintain a substantially constant predetermined distance between the edge 44 and one stitch 42. 20
corresponds to the lateral position that must be occupied.

In summary, when a user wishes to apply a single stitch at a substantially constant predetermined distance from the edge of the fabric, the user sets the sewing machine 10 to the straight stitch mode of operation and turns the edge guiding switch 46 to the ON position. let The longitudinal position of the sensor 52 is adjusted by the user so that the center of the sensor 52 is aligned with the edge 4 of the fabric 32.
4, preferably so that the needle 20 is in its center position. When the sewing machine is then activated, the above-described device compensates for the lateral movement of the fabric 32. The device described above has a needle 20
It is understood that this is only effective within the maximum permissible traverse of . If the fabric 32 deviates laterally from this range, it must be guided into this range by the user.

Thus, an apparatus has been disclosed for sewing a series of stitches at a substantially constant predetermined distance from the edge of a fabric. It is understood that the apparatus described above is merely illustrative of the application of the principles of the invention.
Numerous other arrangements will be devised by those skilled in the art without departing from the spirit and purpose of the invention, as defined by the claims.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a sewing machine incorporating an exemplary apparatus constructed in accordance with the principles of the present invention, and FIG. 2 is a block diagram of an exemplary circuit constructed in accordance with the principles of the present invention. be. Explanation of reference numbers, 10...Sewing machine, 20...Sewing machine needle, 22...Needle bar, 30...Reversible linear actuator, 46...Switch, 50...Edge sensor,
52, 54...Photo sensor, 64...Bite actuator device.

Claims (1)

[Claims] 1. It is movable in the lateral direction with respect to the fabric feeding direction,
In addition, in a sewing machine having a needle capable of reciprocating up and down and a needle lateral movement mechanism for lateral positioning of the needle, it is possible to control the sewing of a series of stitches at a substantially constant predetermined distance from the side edge of the fabric. a stitch position control device for controlling the stitch position, the device comprising: a device adjustable by a user to set a desired position of said side edge; and a sensing device for sensing the actual position of said side edge; If the position does not match the desired position, the actual deviates from its position, and the sensing device generates a signal having a value of 0 when the actual position and the desired position coincide; generates a signal having a first polarity when the actual position and the desired position are deviated, and whose magnitude increases as the distance of deviation between the actual position and the desired position increases; When the actual position deviates along the second direction, the signal has a second polarity, and the magnitude of the signal increases as the distance of deviation between the actual position and the desired position increases. a control device responsive to the signal from the sensing device and connected to the needle lateral movement mechanism, the controller controlling the needle lateral movement mechanism via the needle lateral movement mechanism; A stitch position control device for laterally positioning the needle such that the stitch maintains a constant predetermined distance from the actual position of the side edge.